Neptune,
Works fine on a AMD Athlon 2Ghz, Radeon 9600 Pro EZ 256Mb, 1Gb Ram, 33fps all the time.
I love the terrain very good, I like the path you created, that is excellent work!
The texture must be stretched a lot though, doesn't look to good. I'm assuming you imported the terrain from T.ED as a complete terrain or a few huge ones. I did that at first also (I'm not using T.ED though) and noticed that the textures do get stretched a lot and characters didn't always interact with the surroundings as wanted, they fell through the terrains at times.
After playing and experimenting, I decided to use single mountains only and combine them into landscapes. This way the texture looks much better, characters interact better with them and still excellent speed, even with 40x40 tiles levels. I've you like you can explore my findings at my website
http://www.aeilkema.dds.nl/mega/index.html
Looking forward to seeing more of your findings and experiments!